论文部分内容阅读
由滚动接触疲劳引起的钢轨踏面斜裂纹已成为目前高速铁路在役钢轨无损检测中的重要问题,现有的铁路钢轨超声探伤车(仪)难以检测此类缺陷。采用低频超声表面波方法,沿钢轨长度方向对钢轨踏面斜裂纹进行B扫成像检测。由于钢轨轨头为带圆弧边的矩形截面,在钢轨表面激发和传播的低频表面波已不再是经典的Rayleigh波,而是一类导波,导波的多模式对表面波成像检测形成了干扰。为减小干扰,将空间平均技术应用于钢轨踏面斜裂纹的表面波B扫成像。对人工缺陷试块和钢轨试样的B扫成像实验结果表明,利用空间平均技术能有效的抑制此类干扰,提高信噪比,可对钢轨踏面斜裂纹作快速检测和定位。
The oblique crack of the rail tread caused by rolling contact fatigue has become an important issue in the nondestructive testing of the existing high speed railway in service. The existing railroad rail ultrasonic testing vehicle is difficult to detect such defects. Using low frequency ultrasonic surface wave method, B-scan imaging was performed on the rail tread oblique crack along the rail length. Since the rail head is a rectangular section with a circular arc edge, the low frequency surface wave excited and propagated on the rail surface is no longer a classic Rayleigh wave, but a multi-mode surface wave imaging detection of guided waves and guided waves is formed Interfered. In order to reduce the interference, the space-averaging technique is applied to surface-wave B-scan imaging of oblique cracks on rail treads. The results of B - scan imaging of the artificial defect test specimen and the rail specimen show that the space averaging technique can effectively suppress such interference and improve the signal - to - noise ratio, which can rapidly detect and locate the inclined crack on the rail tread.